Micro-procedures, such as micro-surgery or micro-manipulation, in experimental and/or clinical settings at times require both injection and aspiration of fluids or solutions. Currently available syringe pumps work either in a single injection or aspiration mode. These systems require the user to stop/pause in the middle of a procedure and let go of the specimen or animal, when this may not be possible or desirable, in order to reprogram the control unit to switch modes. Further, reprogramming the control unit in the middle of a procedure is impractical since the operator's hands are typically not free. Moreover, while these systems can deliver preset volumes at preset flow rates, these parameters cannot be changed in real time during injection or aspiration.
In addition, some current systems enable both aspiration and infusion modes using two terminals (i.e., two needles, two cannulas, etc. . . . ), which requires two incisions or entry/exit points. In operation both the injection and aspiration modes are performed simultaneously even when a single mode is desired or required. As a result, these systems do not enable aspiration and/or delivery of the same tissue or liquid. And the preset volumes and flow rates likewise cannot be changed during injection or aspiration.